We propose a viscoelastic/plastic constitutive equation for viscoelastic media based on irreversible thermodynamics and the viscoelastic theory. Uniaxial tensile tests on a TriA-X polyimide resin are performed at different temperatures and strain rates to determine the material parameters for the constitutive equation. In the numerical analysis, the FORTRAN programming language is used to apply the proposed equation to the matrix resin. Transverse tensile failure analysis is performed on the unidirectional carbon fiber reinforced plastic (CFRP) in constant strain rate condition after holding constant strain. In this condition, the failure strength is lower than the static tensile strength. The same tendency is observed in the three-point bending fracture test of the unidirectional CFRP. The proposed model expresses the accumulation of resin damage while holding a constant strain and predicts the residual strength and lifetime of the unidirectional CFRP.

我们基于不可逆热力学和粘弹性理论提出了粘弹性介质的粘弹/塑性本构方程。在不同的温度和应变速率下，对TriA-X聚酰亚胺树脂进行单轴拉伸测试，以确定本构方程的材料参数。在数值分析中，使用FORTRAN编程语言将建议的方程式应用于基体树脂。保持恒定应变后，在恒定应变率条件下对单向碳纤维增强塑料（CFRP）进行横向拉伸破坏分析。在这种情况下，破坏强度低于静态拉伸强度。在单向CFRP的三点弯曲断裂试验中观察到了相同的趋势。